Metal cutter



Patented May 16, 1944 UNITED STATES PAT-ENT FFIC.v

" 2,343,876 k I l METAL CUTTER Charles L. Beard, Lancaster, Pa.' rAppucation August z3, 1943, serial No. 499,667

1 c1aim. (ci. .2o- 247) y My invention relates to power actuatedcuttingA tools for cutting light sheet material in the course of themanufacture or repair of parts made from sheet metal or fibre board,such as automobile and air plane bodies, stove pipes etc., and is animprovement over Patent No. 2,273,376.

One of the objects of the invention is to provide a cutter, which whenconnected to a source of power such as a pneumatic or electric drill,will automatically swing to an operative position, thus leaving one handfree.

Another object of the invention is to provide a cutter adapted to bedriven by practically any size of drill.

A still further object f the invention is to provide a cutter which canbe conveniently and effectively applied in cutting out sections ofdamaged sheet material in making repairs.

These and other objects and advantages of the invention will be apparentas the specication ls considered with the accompanying drawing, inwhich:

Figure 1 is a side elevation of the cutter;

Figure 2 is a fragmentary view of the front end of the cutter showingthe cutter blade inserted through a hole in a piece of material beingrepaired; 1

Figure 3 is a longitudinal section through the cutter;

Figure 4 is a section on the line 4-4 of Figure 3;

Figure 5 is a front view of the cutter; and

Figure 6 is a plan view of a piece of material showing a damaged sectionmarked for repair.

Referring more particularly to the drawing, I designates a body,preferably of cast metal, bifurcated at its front end or nose to definefixed top cutting blades or jaws 2. The blades or jaws 2 are formed byslotting the body I, as at 3, and the cutting edges thereof are providedwith inserts 4, of hardened steel or other suitable material adapted toenhance the cutting proper*- ties of the tool.

The body I, is formed with a downwardly and forwardly inclined flat topface I5 and a straight flat bottom face 5, in the latter of which is cuta relatively deep longitudinally disposed slot 6, for the reception of alower movable cutting blade l, suitably mounted therein by means of aremovable threaded pivot pin 8. The forward or cuttingA end 9 of blade Iextends into and through the end slot 3, the latter, in effect,constituting a continuation of the slot B, the blade being thusinterposed between and shielded bY the relatively heavy fixed cuttingjaws or blades 2. A tail portion I0 of movable blade 'l is engaged by acam follower or plunger II, slidably seated in a circular opening I2formed in the body I, and a coil spring I3, seated in a suitable openingI4, engages the blade l, forwardly of the pivot 8, and normally tends tohold the blade in open position, as will be more fully explainedhereinafter.

The bottom faces of the fixed jaws or blades 2 are inclined upwardly andforwardly as at I5 and converge with the top face I5, to form a nose Il,and the shape of the movable cutting blade 1 is such that the cuttingedge I8 thereof will normally form an acute angle with the cutting facesI6 of the xed jaws. Thus the blade I is formed with a straight fiatbottom edge or wall I9, extending throughout the greater part of itslength, and which normally lies parallel to and flush with the bottomface 5 of the body I. The cutting end 9 of the blade 1 is formed with acurved bottom edge 20 which merges with the downwardly and forwardlyinclined cutting edge Extending into the body I is an operating shaft2I, provided with a double lobed cam 22. The lobes of this cam are inalinement with and successively engage the cam follower or plungei` I I,which action will rock the blade l, on its pivot pin 8, at a rapid rateof speed, thereby moving the forward or cutting end of the bladerelative to the companion or fixed blades 2 between which it operates.Bearings 23 and 24 are provided through which the operating shaftextends and a pin 25 prevents accidental removal of the shaft andbearing assembly.

The operating shaft is so constructed as to be received in the bit chuckof an electrically or pneumatically driven hand drill for considerationsof portability and general convenience. Thus when the free end of theshaft 2I is in the bit chuck of a drill, not shown, the eccentricmounting of the shaft will cause the tool to automatically swing tooperative position thus leaving one hand free.

In practice, assuming that it is desired to cut a damaged section 26,from a sheet metal part 2l, the operator merely drills or otherwiseforms holes or openings 28 defining the area to be removed and ofsufcient size to receive the cutting end 9 of movable blade l. Theportion 9 of blade l is then inserted in one of the holes 28 and cutsmade from one hole to another until the damaged or defective section hasbeen severed and removed.

By virtue of the shape of the part 9 of the blade 1 and the nose part l1of the fixed jaws or blades 2, the movable cutter blade can be readilyinserted in the hole 28 and the tool can be conveniently used in closedquarters and with any size of electric or pneumatic drill. Thus, asillustrated in Figure 3 of the drawings, when the movable cutter hasbeen inserted through the work to be cut, the'upwardly and forwardlyinclined bottom faces I6 of the fixed cutters will rest upon and slideover the work, the rear end of the tool and -power drive element beingtilted or elevated for'this purpose. This permits of the use of a muchlarger drill than otherwise could be accommodated, and the iiat orstraight oppositely inclined faces I6 and I8 of the pointed upper andlower cutters respectively permit of quick and accurate adjustment ofthe blades with respect to the work.

It will be understood that when the operating shaft is actuated the cam22 will force the tail.

of the blade 'l downwardly and the cutting edge upwardly against thetension of spring I3 and that the spring returns these members to theirnormal inoperative positions.

Having thus described my invention, what I claim is:

A cutting tool comprising a body having a ilat horizontally disposedlower face throughout a greater portion of its length and oppositelyinclined upper and lower faces converging at the front end of said body,said lower inclined l0 face merging with said horizontal face, saidfront end having a slot formed therein to define parallel xed blades,said horizontally disposed lower face having a longitudinally disposedslot therein communicating with said first mentioned 15jslot, a Vmovableblade pivotally mounted in said last mentioned slot for reciprocatorymovement between said xed blades, said movable blade having a lstraightcutting edge disposed at an acute angle to said lower inclined faces,and

20 means for rocking said movable blade on its pivot. Y Y

CHARLES` L. BEllHRD.v

